The present invention relates to an apparatus and technique for increasing the efficiency of operation of an internal combustion engine and more particularly to an improved apparatus and technique that permits control of generated pressures and temperatures during combustion of fuel in the combustion chamber of an internal combustion engine for achieving predetermined parameters of pressure and temperature within the combustion zone in order to decrease the amount of pollutants exhausted by the engine during operation.
Efficient conversion of energy into useful work has been the goal of engine designers since the creation of internal combustion engines utilizing the Otto cycle, i.e. reciprocating, rotary, diesel engines and the like. In view of the scarcity and high cost of engine fuels, engineers and engine designers have been grappling with the fundamental problems of exhaust emission pollutants and increased fuel economy, yet striving to improve performance in these areas without sacrificing engine performance and efficiency. This has produced internal combustion engines that are operating in a critical compromise of fuel/air mixture composition, pressure and temperature that results in the engine generating and discharging harmful pollutants (CO, NOX, and HC) in order to achieve adequate performance.
To deal with the NOX emissions designers have retarded spark and employed such devices as exhaust gas recirculation systems, each which decreases overall engine performance, with a resultant decrease in engine performance and which further cause increases in HC and CO emissions. These increased HC and CO emissions must be cleared up by expensive catalytic converters which in turn require unleaded fuels.
Continued distortion of the combustion process in internal combustion engines can only result in a hodge potch of engine control devices that increase engine manufacturing cost and result in low engine performance with low fuel economy.
Realization in both industry and the government that internal combustion engines will require drastic design changes to achieve permissible government pollution standards has resulted in considerable developmental efforts to investigate the combustion process. These efforts have results in various techniques such as changing the size and shape of the combustion chamber, relocation of the spark within the combustion chamber, the use of multiple-source ignition schemes and the use of stratified charge designed combustion chambers.
Various modifications of a combustion chamber shape into a hemispherical chambers with changes in conventional spark locations by designing spark plugs with extended gap designs has reduced HC emissions but this design has mechanical manufacturing difficulties that far out weigh the amount of reduced emissions obtained.
Another technique presently being utilized is the use of a multiple-source ignition configuration to cause creation of a torch-like flame to about into a homogeneous-lean air/fuel mixture within the combustion chamber with the torch fueled by the same fuel as the main chamber. The torch ignition mixture is mechanically separated from the main chamber by an antechamber constructed in the engine head to open into the main combustion chamber.
Another popular scheme is the stratified charge engine (SC) configuration which can have numerous variations. The basic idea of the SC engine involves introduction of a rich, easily ignitable mixture in the vicinity of the spark plug and a very lean mixture throughout the rest of the chamber, so as to have a differing air/fuel ratio in various areas within the cylinder chamber, rich in some lean in others, with the resulting overall air/fuel ratio considerably leaner than stoichiometric. The burning takes places in stages with a small volume of rich air/fuel mixture being ignited first to create a flame that spreads out into the combustion chamber charged with very lean air/fuel mixture causing ignition of these areas more thoroughly and burning them more completely then in conventional internal combustion engines.
The above are a few of the more pertinent devices of the numerous proposals that have been set forth to reduce pollution and increase engine and fuel performance. Each has some distinct disadvantage because of its interaction with other engine parameters inherent in the Otto cycle or diesel cycle engine. In view of this there has been created a need in the industry of an internal combustion engine operating on a gas cycle that has the characteristics of the Otto cycle but which has a process of combustion that is time controlled and will operate with the advantage of high compression ratio and fuel rich air ratios with the efficiency and total fuel oxidation of the diesel without its disadvantages of high pressure, high temperature and knock tendency.
Accordingly, the present invention has been developed to overcome the specific shortcomings of the above known and similar techniques and to provide an improved apparatus and technique for generating a heat balanced cycle for internal combustion engines with performance, pollution characteristics, and a multifuel burning capability that is not present nor possible with conventional Otto or diesel cycle engines.